-LRB- CNN -RRB- -- Cristiano Ronaldo scored the only goal of the match with a stunning backheel as Real Madrid beat Rayo Vallecano to stay 10 points clear in the Spanish title race Sunday .

Real had to work hard to emerge on top in the capital derby at the Vallecas while arch-rivals Barcelona won 2-1 against Atletico Madrid in the late kickoff to avoid falling further behind Jose Mourinho 's men .

The reigning champions owed their win to a Lionel Messi free-kick in the 80th minute . It was his 28th league goal of the season , one fewer than Ronaldo .

Dani Alves opened the scoring on 36 minutes but Radamel Falcao equalized at the beginning of the second half for the home side .

Earlier , the first half of the clash between the Madrid rivals was short of chances , but Rayo came closest to scoring as Michu rattled the woodwork with Iker Casillas beaten .

Ronaldo struck shortly after the break following a corner . He was running away to chase a loose ball , but then fashioned an incredible backheeled effort which flew into the net .

`` A backheel is always different . It was a great goal but I 'm not sure if it was the best of my career -- I have to see it again on TV , '' Ronaldo told AFP .

Jose Callejon later wasted a chance to double the lead for Los Blancos to calm their nerves .

Ronaldo was also denied a second by home keeper Joel late on before the home side lost Michu to a red card for a rash challenge .

It was Real 's 21st league win of the season .

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Real Madrid win 1-0 at Rayo Vallecano to stay top in Spain

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Stunning backheeled effort from Cristiano Ronaldo settles game

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Real stay 10 points clear of Barcelona in title race

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Lionel Messi with winner for Barca at Atletico Madrid